Writing instrument barrel



FIG. 1 is a perspective view of a writing instrument barrel showing our new design;

FIG. 2 is a left side view of the same writing instrument barrel, the right side view being identical to the left side view;

FIG. 3 is a front view of the same writing instrument barrel, the back view being identical to the front view;

FIG. 4 is a top view of the same writing instrument barrel; and,

FIG. 5 is a bottom view of the same writing instrument barrel.

The broken lines shown in the drawings illustrate features of the article to which the design is applied that form no part of the claim. 

We claim the ornamental design for a writing instrument barrel, as shown and described. 